The goal is to determine whether Ca++ and other channels in the membranes of vascular muscle cells contribute to age-related changes in blood pressure. The basic cellular investigations of blood vessels described have significance for knowledge that will lead to prevention and treatment of a number of cardiovascular disease processes, notably hypertension, stroke, and coronary artery disease. The methods for these investigations include studies of isolated single cells with powerful new techniques to allow determinations of membrane and subcellular alterations important for increases in blood pressure. Procedures and apparatus for the careful isolation of single vascular muscle cells from both arteries and veins, refined for over a decade in this laboratory, will allow studies on membrane excitation, excitation-contraction coupling, and alterations in membrane function. Specific aims in these experiments include patch-clamp investigations of Ca++ channels, K+ channels, Na+ channels, and interactions of ions, especially Ca++ with both Na+ and K+ channels. In addition, intracellular localization and quantitation of Ca++ will be carried out using the Ca++ indicator, fura 2. Recordings of Ca++ currents, K+ currents and Na+ currents in vascular muscle cells will allow studies of activation, inactivation, and modulation of ion channels important for excitation, contraction, and relaxation in vascular muscles. Studies of Ca++-activated K+ conductance, Ca++-inactivated Ca++ conductance, and Ca++-inactivated Na+ conductance will reveal important Ca++ interactions potentially related to altered contraction. One portion of the project will explore the trophic influences of adrenergic nerve endings on changes in the ion channels with aging. Coordinated studies of movements of ions through vascular muscle cell membranes with quantitative localization of intracellular Ca++ will allow these cellular mechanisms contributing to changes of blood pressure with aging to be understood.